电沉积微纳米镍的组织结构与力学性能  

Microstructures and mechanical properties of electrodeposited microcrystalline and nanocrystalline Ni

作　　者：许伟长[1] 戴品强[1] 

机构地区：[1]福州大学材料科学与工程学院,福州350108

出　　处：《中国有色金属学报》2009年第10期1815-1821,共7页The Chinese Journal of Nonferrous Metals

基　　金：福建省自然科学基金资助项目(E0810006)

摘　　要：在氨基磺酸镍体系的镀液中通过直流、脉冲电沉积分别制备了不同晶粒尺寸的块体镍。通过室温单向拉伸实验比较了这些镍的力学性能。结果表明:拓宽电沉积纳米镍的晶粒尺寸分布可显著提高其塑性,同时,保留较高的强度。所制备的具有宽晶粒尺寸分布(5～120nm)的平均晶粒尺寸为27.2nm的纳米镍,抗拉强度为1162～1211MPa,断裂伸长率为10.4%～11.4%。与平均晶粒尺寸为22.4nm的窄晶粒尺寸分布(5～60nm)的纳米镍相比,抗拉强度降低约200MPa,但断裂伸长率提高了3.4%。通过对纳米镍微观组织的TEM观察,揭示了宽晶粒尺寸分布纳米镍中塑性的显著提高源于塑性变形中大晶粒(100nm以上)内存在类似传统粗晶材料中的晶内位错滑移。The bulk Ni with various grain sizes were prepared by direct current or pulse electrodeposition, respectively, in the nickel sulfamate electrolyte. The uniaxial tensile tests were performed at room temperature to compare the mechanical properties among these Ni samples. The results show that the ductility in electrodeposited nanocrystalline （NC） Ni can be significantly enhanced with a higher strength by extending the grain size distribution. The NC Ni samples with a broad grain size distribution （5-120 nm） and an average grain size of 27.2 nm have an ultimate tensile strength （σUTS） of 1 162-1211 MPa and an elongation to failure （δETF） of 10.4%-11.4%. Compared with the NC Ni samples that have a narrow grain size distribution （5-60 nm） and an average grain size of 22.4 nm, the σUTS ofNC Ni with a broad grain size distribution decreases by 200 MPa, but the δETF increases by 3.4%. By the TEM observations of the microstructures in NC Ni, it is revealed that the apparent enhancement of ductility in NC Ni with a broad grain size distribution results from the presence of intragranular dislocation sliding in the large grains （above 100 nm） during plastic deformation, similar to that in conventional coarse-grained materials.

关 键 词：纳米镍 力学性能 变形机制 电沉积 

分 类 号：TG174.441[金属学及工艺—金属表面处理]